Carbon alignment device for arc lamps



Oct. 5, 1948. H. l. HUFF 2,450,477

CARBON ALIGNMENT DEVICE FOR ARC LAMPS I 2 Sheets-Sheet 1 Filed Dec. 5, 1946 Oct. 5, 1948.

Filed Dec. 5, 1946 H. l. HUFF CARBON ALIGNMENT DEVIQE FOR ARC LAMPS 2 Sheets-Sheet 2 FIG-n Z Patented Oct. 5, 1948 CARBON ALIGNMENT DEVICE. F ARC LAMPS Harold I. Huff, Los Angeles, Calif.

Application December 5, 1946, Serial No. 714,251

6 Claims.

This invention relates to a carbon alignment device for an arc lamp and is particularly directed to an attachment found particularly useful in connection with a conventional form of arc lamp now in general use.

One of the recognized problems in operating an arc lamp of the type employed for motion picture projection is that of maintaining the alignment of the carbons so that the crater formed on the positive carbon remains in the proper plane and position with respect to the concave mirror used for concentrating the light on the lens system. In arc lamps utilizing axially aligned carbons, difficulty is frequently encountered in maintaining the carbons in correct alignment. The carbons are gradually bent away during the operation thereof and the heat generated is instrumental in bringing about conditions of misalignment so that insufiicien-t light is concentrated on the lens system and the result i that the picture on the screen appears to be inadequately and non-uniformly lighted.

The principal object of this device is to overcome the difiiculty in providing convenient adjustment means so that optimum conditions of carbon alignment may be easily obtained at any time.

A more specific object is to provide a novel device for attachment to the conventional mounting of the negative carbon, whereby proper alignment may be secured by manipulation of one of a pair of adjusting screws.

Another object is to provide a pair of stationary element on the frame of an arc lamp for projection through spaced apertures provided in a carbon-carrying member, providing a slot in the member adjacent the lower stationary element to permit vertical movement of the member and providing adjusting means at the upper stationary element for moving the member vertically or in an are about the lower element acting as a pivot. I

Other objects and advantages will appear hereinafter.

In the drawings:

Figure 1 is a perspective view of a preferred embodiment of my invention, shown in connection with a conventional form of arc lamp employed for motion picture projection;

Figure 2 is a transverse sectional elevation of the arc lamp, illustrating the alignment device embodied in my invention;

Figure 3 is a partial sectional view taken substantially on the lines 33 as shown in Figure 4;

Figure 4 is a partial end view of the arc lamp assembly, showing details of mounting of my alignment device;

Figure 5 is a sectional plan view, taken substantially on the lines 55, as shown in Figure 4.

Figure 6 is a perspective view of the reference element employed in connection with my alignment device;

Figure 7 is a perspective view, showing details of construction of a bushing employed in connection with my invention;

Figure 8 is a sectional elevation, taken substantially on the lines 88 as shown in Figure 4.

Referring to the drawings, the arc lamp generally designated I0 is provided with a frame ll composed of a plurality of individual parts secured together by any convenient means and movably mounted on the frame II is a carrier I2 for the positive carbon l3. Means are provided for supporting a negative carbon M in axial alignment with the positive carbon 1 3 and, as shown in the drawings, this means includes a movable support member l5, which is provided with a lower aperture l6 and an upper aperture l6 Supported on the member I5 is a carrier ll for the negative carbon l4 and this carrier includes a power actuated advancing mechanism I8 for feeding the negative carbon M axially toward the positive carbon 13. The advancing mechanism includes a driving gear I9 and a driven rack 20, as shown in Figure 2. The usual permanent magnet 2! is provided for stabilizing the arc, which is drawn between the carbons l3 and M. The carrier ll, together wtih the advancing mechanism l8 and associated parts are supported on the member l5 by means of the bolts 22. As pointed out above, it is important that the crater 23, which forms on the end of the positive carbon be maintained in a proper position so that the light therefrom is directed substantiallyuniformly over the surface of the concave reflecting mirror 24 in order that the optimum quantity and quality of light be obtained. Should one or both of the carbons be deflected or distorted out of their optimum position, the resulting crater 23 no longer is at right angles to the axis of the lamp as a whole. Means are therefore provided for adjusting the position of the negative carbon to compensate for errors in alignment, which may arise from any cause. As shown in the drawings, this means includes an upper stationary element, which may takethe form of the bolt 25 and a lower stationary element or eccentric bolt 26. These bolts are each fixed to a portion of the frame I I; thus, the bolt 25 is provided with a shoulder 21, so that the nut 28 clamps the ear 29 on the frame II between the nut and the shoulder. Likewise, the nut 30 clamps the ear 3| on the frame I I between the nut and the shoulder '32. The bolt 26 is provided with an eccentric portion 33, which extends through the aperture I6 in the lower end of the support member I5. A bushing 34 is provided with a serrated cylindrical surface 35, which .is adapted to be pressed into the aperture I6 and prevent relative rotary movement between the bushing 34 and the support member I5. The bushing 34 is inserted into the aperture I6 in a position such that the elongated slot 36 in the bushing '34 is disposed in thedirection of the length of the support member i5. As shown in thedrawings, the member I may be mounted vertically and, accordingly, the slot 35 is also positioned vertically. A nut 31 is threaded on the projecting end 38 of the bolt member 25 and a washer 36 is clamped against the end face 48 of the bushing 34 by means of this nut. The nut 31 is not tightened solidly against the washer 39, but is threaded by hand until a certain amount-of frictional resistance is encountered. The eccentric portion 33 of the bolt member 26 remains stationary, while the support member I5 and bushing 34 are free to move vertically with respect thereto. The eccentric portion 33 of the bolt 25 has a sliding fit between the side of the vertical slot 36.

The nut 4| is threaded on the projecting end 42 of the bolt 25 and the nut is turned only to a hand-tight position in a manner similar to that described for the nut 37. The central portion 43 of the bolt 25 has a substantial clearance within the aperture I'I formed in the upper-end of the support member l5, so that relative move ment of the upper end of the support member I5 may occur in any direction in a plane normal to the axis of the bolt 25. A reference element or angle piece 44 is provided with three sides 45, 46 and 41, which are mutually at right angles, as shown in Figure 6. A vertical slot 48 is formed in the side 45, a horizontal slot 49 is formed in the side or bottom 45, and an opening 56- is formed through the side wall 41. The opening5l is adapted to receive the projecting end 42 of the bolt 25. A bracket 5i, having a'bottom plate 52 and an upstanding flange 53 is provided with a clamping plate 54, which is attached tothe bottom plate 52 by means of the machine screws 55. A recess 52 is formed in the bottom plate 52, which is adapted to receive a portion of the support member I5 and, as shown in Figure 5, the screws 55 are adapted to clamp the member -I5 between the clamping element 54 and the bottom plate 52. Threaded into the bottom plate 52 is a primary adjusting screw 56, having a knurled head 51. Threadedinto the flange 53 is a secondary adjusting screw 58, having a knurled head 59. The projecting end of the primar adjusting screw 56 passe through the horizontal slot 49 and the projecting end of the secondary adjusting screw 58 passes through thevertical slot 48.

The projecting end 60 on each of the adjusting screws passes through washers Si and 52, pcsitioned on each side of the slot, and is held in place by a pair of nuts 63 threaded on the projecting end 64 of the adjusting screw. The nuts 63 are locked on the thread portion 54 but leave sufficient clearance to prevent clamping or seizure of the washers 62 on the opposite sides of the elongated slot.

From this description, it will be understood .ment.

that turning of the primary adjusting screw 56 serves to rotate the screw relative to the bottom plate 45 of the reference element 44 and since the element 44 is stationary, the support mem-- ber I5 is moved vertically, with the slot 36 in the bushing 34 moving relative to the bolt 26. Such vertical movement is not opposed by the connection between the secondary adjusting screw 58 and the reference element 44, since the vertical slot 48 is adapted to accommodate such move- In a similar manner, turning of the secondary adjusting screw 58 relative to the upwardly extending flange 53 on the bracket 5I serves to move the upper end of the member I5 horizontally or, in other words, cause the support member I5 to travel in an arc about the eccentric portion 33 of the bolt 26 as a pivot. Such lateralmovement of the upper end of the'support member I5 is not opposed by the connection between the primary adjusting screw 56 and the reference element 44 because the horizontal slot 49 in the bottom plate 45 is adapted toaccommodate such movement.

In operation, the nuts 28 and '35 on the back side of the bolts 25 and 26, respectively, are first tightened, the nut 28 being tightened with a wrench and the nut 30 being screwed only hand tight. A screw driver is inserted into the slot provided in the projecting end 38 of the bolt 26 and the bolt i turned until the carbons I3 and I4 are brought into vertical alignment. The nut 35 is then brought up solid by means of a wrench. The primary adjusting screw 57 is then turned to raise or lower the support member I5 to bring the carbons I3 and I4 into horizontal alignment. The arc lamp is then ready for its normal operation, which need not be described in detail here. Should the carbons fall out of alignment for any reason, such as, for example, warping (due to heat), failure of short stub sections to align perfectly, etc.,' the adjusting screws 56 or 59 may be turned to bring the carbons back into alignment. Further adjustments may be made from time to time, in order to preserve accurate alignment between the adjacent ends of the carbons I 3 and I4.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claims.

I claim:

1. In an apparatus for laterall adjusting one of a pair of axially aligned carbons for an arc lamp, the adjustable carbon being carried on a support member movably mounted on a frame, the combination of a pair of spaced stationary elements fixed on the frame and projecting through spaced apertures provided in the support member, means providing a slot at one of the apertures adapted to cooperate with the first stationary element to permit linear movement of the movable member in one direction relative to the frame, primary adjusting means associated with the second stationary element adapted to move the support member linearly in said direction, and secondar adjusting means associated with said second stationary element adapted to swing the support member in an are about the first stationary element.

2. In an apparatus for laterally adjusting a pair of axially aligned carbons for an arc lamp, the adjustable carbon being carried 'on a support member movably mounted on a frame, the combination of a pair of spaced stationary elements fixed on the frame and projectingthrough spaced apertures provided in the support member,

a reference element fixed on the projecting end of one of the stationary elements, cooperating means on the support member and the other stationary element permitting linear movement of the adjacent end of the support member in one direction only, a bracket, means for attaching the bracket to the support member, primary adjusting means on the bracket cooperating with said reference element for linear movement of the support member in said direction, secondary adjusting means on the bracket cooperating with the reference element for moving the adjacent end of the support member in an arcuate path with said cooperating means acting as a pivot.

3. In an apparatus for laterally adjusting one of a pair of axially aligned carbons for an arc lamp, the adjustable carbon being carried on a support member movably mounted on a frame, the combination of a pair of spaced stationary elements fixed on the frame and projecting through spaced apertures provided in the support member, means providing a slot at one of the apertures adapted to cooperate with the first stationary element to permit linear vertical movement of the movable member relative to the frame, the first stationary element having an eccentric portion for varying the position of the path of vertical travel of said support member, pjrimary adjusting means second stationary element adapted to impart vertical movement to the support member, and secondary adjusting means associated with said second stationary element adapted to swing the support member in an are about the eccentric portion of the first stationary element.

4. A carbon alignment attachment for an arc lamp having a frame and a carbon-carrying support member, comprising in combination a first stationary element fixed on the frame and provided with an eccentric portion, a bushing in the support member provided with a vertically extending slot adapted to receive said eccentric portion of the stationary element, said stationary element being turnable to a selected position to provide a lateral adjustment of the bushing, a second stationary element fixed on the frame remote from the first stationary element and projecting through an aperture provided in the support member, a reference element fixed on the projecting end of said second stationary element, primary adjusting means associated with a second stationary element adapted to impart vertical movement to the support member, and secondary adjusting means associated with said second stationary element adapted to swing the support member in an are about the eccentric portion of the first stationary element.

associated with the e 5. In conjunction with an arc lamp having a frame and employing a pair of axially aligned carbons, one mounted on the frame and the other carried by a support member, the improvement comprising a pair of spaced stationary elements fixed on the frame and projecting through spaced apertures provided in the support member, means associated with one of the stationary elements and permitting vertical sliding movement of the support member relative thereto, and a plurality of adjusting means associated with the other station'ary element adapted to move the support member in avertical direction or to swing it about the first stationary element as a pivot.

54 In an apparatus for laterally adjusting a pair of axially aligned carbons for an arc lamp, the adjustable carbon being carried on a support member movably mounted on a frame, the combination of a pair of spaced stationary elements fixed on the frame and projecting through spaced apertures provided in the support member, a reference element fixed on the projecting end of one of the stationary elements, cooperating means on the support member and the other stationary element permitting linear movement of the adjacentend of the support member in one direction only, a bracket, means for clamping the bracket to the support member, a primary adjusting screw threaded on the bracket, a slot on the reference element adapted to receive one end of said primary adjusting screw whereby turning the screw relative to the bracket serves to move the support member vertically, a secondary adjusting screw threaded on the bracket, a second slot on the reference element adapted to receive one end of the secondary adjusting screw, and cooperating means on the support member and the other stationary element adapted to permit angular and vertical movement of the support member relative to the said other stationary element.

HAROLD I. HUFF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

